This invention relates to a jewelry clasp for use in bracelets, necklaces and the like. With the devices employed for this purpose in the prior art a common complaint has been the need for handling of very small locking mechanisms by persons with long finger nails. It is often necessary to obtain help from others when putting on jewelry and again when removing it. Existing devices are relatively complex and expensive to manufacture while simpler mechanisms are not secure enough with the result that a valuable piece of jewelry may become undone and be lost especially when the wearer puts on or takes off close-fitting outer wear.
The most commonly used device in the prior art has been a pair of loops one of which contains a spring loaded plunger spanning a narrow gap in the loop and an externally protruding activator pin. The other loop is uninterrupted. Each loop is attached to one free end of the bracelet or necklace. To fasten the jewelry requires the loops to be held close together at an approximate right angle. The plunger is retracted with a finger nail or bottom of a finger, the loops interlocked and the plunger released. With long finger nails it is difficult to retract the plunger. An early improvement in the art is represented by Houdy(French patent 547,608); this uses a principle more recently utilized in coaxial electrical connectors--i.e. one half of a cylindrically shaped clasp is hollow and provided with a J-shaped slot in its side and contains a spring. The other half of the clasp is smaller and contains a radially-oriented pin. The second half of the clasp is inserted into the first so that the pin enters the slot. Further insertion compresses the spring. The second half is then rotated so that the pin enters the curved portion of the J-shaped slot where it is retained under spring tension. Although this clasp is useable with long fingernails, it is difficult to unlock when made in small sizes.
A clasp using a somewhat different principle is taught by Murso (U.S. Pat. No. 4,532,682). One part of the clasp is provided with a collapsible tongue and a release trigger. The second half contains a slot which fits the trigger and an opening to accommodate the trigger. This construction provides good adherence of the two halves of the clasp when it is joined but is difficult to use with long nails. It is complex and relatively expensive to manufacture.
It is one objective of the present invention to permit opening and closing without the use of external release devices.
It is a second objective to achieve simplicity in manufacturing and low production cost.